Memory is built on 3 components:

1. Impression 2. Association 3. Repetition

A single one of these components can be enough to memorize anything. However, weaving the 3 components together is the most secure way to remember anything - once and for all.

Let me illustrate each component:

Impression: When you are very impressed by something (an idea, a picture, a sound, a face, a text, a situation...), the probability that you will remember it is much higher. For example, if as a child you were left alone lost in a mall for a while, you might remember the whole situation very accurately. Same with your book: if you are very impressed by something Thomas Jefferson did in his life, the chance to remember this part becomes higher. Now the good thing is that you can increase the strength of this impression yourself while reading. For example, you can stop reading one second and picture the situation in your mind, exagerating some features of the situation in order to enhance the impression of your mental image, by adding violence or greatness or anything to shock yourself. You can even add yourself in your mental picture, imagining Thomas Jefferson thanking you for your help or kicking your butt or anything like this. This will make the impression stronger.

Also, you may enhance the impression of a text by reading it out loud, even very loud if your neighbors are OK with it; some people are more sensitive to impressions coming from sounds (voice) than from the view (written text).

Association: If you can link something you read to anything you already know, the probability of remembering it becomes even stronger, sometimes incredibly strong. For example, if Thomas Jefferson was born on the same day as you, you would find it very easy to remember this, because you linked the data you read to something you already know for sure and will not forget. It is like tying something new (the data you read: Jefferson's birthday) to a tree (a piece of data you know: your own birthday) with a rope (the same date). That is why the more you know about a topic, the easier it is to learn more and more.

If you are very knowledgeable on a topic (like Christopher Hitchens and Sam Harris on literature), it becomes very easy to make strong links -- you have many ropes and many trees... So learn more about the basics and about the context of a book and you will remember more.

Repetition: If you read a book 10 times you will remember more. Same for anything, a recipe, a route between 2 locations, the lyrics of a song, phone numbers... The more you repeat, the more you remember. When reading a book, if you do not want to read it several times, you can highlight a few parts that you want to remember, and re-read only those parts several times. These parts you will remember much better. And you will see that actually they will also help you remember the rest of the book.

In summary: Impress yourself with powerful mental images, make associations with what you already know (and make sure you learn the basics before you learn more), and repeat this exercise several times. Work to become better at remembering and you will become better at remembering everything you want.

As a philosophy student, I often need to read multiple long texts and synthesise the most important information from them. This is different from reading a textbook, because textbooks are (usually) more dense than prose.

This is my strategy to gain information on a subject from books:

Notes

• While you are reading, take notes. Short notes, just to remind yourself of what you've read. Key words, quotes that speak, etc.
• After each chapter, rewrite your notes. Write at a higher level than the notes you took when you were reading. Because you now have all the information on a given chapter, which you didn't have whilst you were reading, these notes should be significantly different and more concise than the previous notes.
• After finishing a book, rewrite your notes again. Again, these notes should be more concise, and at a 'higher level', than the previous notes.
• Read some other books on the subject an repeat the strategy outlined in the first three bulletpoints.
• After having read a number of books, we take it one level further; you will write notes on the subject of the books. Try to write down as much as you can from memory, but also use all of the (book-level) notes if necessary.

Interaction

• Write as much as possible about what you are reading. Write a blog, write book reviews, etc. Perhaps even make a Youtube video about your thoughts on the matter, if you're into it.
• Debate the content of the book. If you have a blog, enable comments. While comments on blog aren't always of the highest level, to put it mildly, it will force you to engage with the material. If you are reading books on politics, perhaps join a debate club.

General advice

What's important in everything that I mentioned is that you create content, rather than merely consume content.

Also make sure that you spread out reading over a long period of time. It's better to read one book a week than to read five books in one week and then do nothing in the next four weeks. Spaced repetition is critically important; make sure that you keep engaging with the material in one way or another.

My answer is along the same vein as others, with a focus on repetition. Different people will learn best working with details/content in different ways, but the key is to work with the material.

By "work with the material" I mean that you have to immerse yourself in these details (reading, listening, sharing, discussing, summarizing, diagramming, writing) and eventually scaffold and present these details to others. You have to have familiarity with some of the details first, but to effectively summarize and present information to others you have a direct reason and application for making this information readily available to your conscious memory. Think about it... to explain it naturally to others, you have to practice communicating those details to others. Toastmasters illustrates this in practice.

If your sole purpose is to help yourself remember details, and time is no object, I would suggest the following approach:

1. Before reading the book, read some reviews or summaries of the work you are about to dig into. This will set some perspective, and introduce main concepts that you can watch for as you read.
2. Read the book from beginning to end, only "bookmarking" particularly memorable or noteworthy items.
3. At a high level, note the main concepts you wish to recall or use.
4. Treat each concept as a research subject and delve back into the relevant areas to dig out supporting details.
5. Construct a synopsis, weaving together related details.
6. Present, discuss and/or debate with others to practice recall of the details. Even if you only produce one final product or presentation, by that time you won't be an expert, but you will have this information in your conscious, working memory. The more you spend time working with the material, the more likely you are to make lasting memories.

Note: Like many things, your memory recall will fade over time if you don't actively reflect on or recall it. Reading your own notes will bring back details more quickly, in my opinion, because you actively constructed that information and the connections will be stronger than simply rereading the book/source material again or reading summaries or notes written by others.

The best method I know of is to read something with the intent of teaching someone else what you have just learned. You will be amazed how differently you consume content.

I absorb information better if it comes in the form of the spoken word. Most books I read nowadays are in audiobook format. I also listen to text to speech sythesis versions of the books if the auidobook has not yet been recorded. I'll even listen to itunesU lectures, podcasts and vieo training courses.

If the item is interesting enough I will listen a few times over. I have a long commute so I am able to take advantage of long listening periods.

I read a lot of non-fiction books and i read it only once. I read it very slowly and imagine myself in that situation, which helps me remembering the people in the story, their quotes. I try to find the hidden meaning behind every quote they say so that i can apply those in real life when speaking to anyone.

I got a real improvement of comprehension after I've learned to use fast reading techniques. I read a chapter then I review it. During the reading I use a pencil to mark with a star what paragraph or sentence seems interesting. I use just one simbol. Many symbols doesn't help at all and I think it slows the reading process. In the review stage I read only what was marked. The next step consist in making notes with my own words.

From time to time I also build mind maps of the book that I've read. But is not always the case. Visualizing the mind map comprehension and retention gains a real boost.

Two small things I've learned when trying to learn from books

1 - Don't skip the contents pages

With non-fiction technical books, it can feel like the list of contents is just more padding at the beginning. When you're just starting the book and are keen to get into the meat of the text, it can be tempting to skip this bit. I've found from experience, that reading the contents pages carefully first creates a mental skeleton structure that everything else can hang off. Without doing this, I find I can dwell overly long on minor details early on, at the expense of more significant topic areas later in the book.

2 - Pick the best time of day

I'm very much a morning person, and I find that I can take in and retain all kinds of written material much better early in the morning, compared to the rest of the day. Work out what time of day is best for you, and try an get your reading done then.

Each time I read a book I want to be able to remember as well as possible, I take 2 hours to summarize its content, and to write the details on 1-2 pages. This way, I can read the resumé when I want later. Moreover, the fact that I have written it make me better at remembering it.

And you are likely to hate this one, but taking handwritten notes helps cement information in your memory. Stop just reading and do something active with what you read. Typing seems to be less effective because it engages less of your brain.

A few ideas to test depending on your learning style:

• Along your reading having a mind map with key items helping you relocate specific location, actions, facts, people etc.
• A friend of mine is part of a reading club. It sounded to me like an activity for older people but she is 35 and she loved it cause from the discussions, this made you think about the book, remember stuff, make new associations of ideas etc, and also seeing how others perceived. If not a reading club, find someone in paralell reading that you can exchange with? (you can even create the system to find someone in the world reading the book in the same time to exchange once completed! then you sell to Amazon to make it a kindl feature and get rich so you can just read books :) !?) ahah
• Recommending the book once you have read it because this will make you think about and name why you would recommend it and key things you took out of it, then you can talk about it with the person you gave it to and therefore refreshing it linking it to people around you.
• Many online tools / apps exist to document your lessons learnt from readings ... most commonly, you can keep a journal of your readings focusing a few standard questions (ex: Date started / finished? Nb pages? what's the story about? what's the ending? Why did I like it / not like it?)

Hope this will give you some ideas! Happy reading